Polymorphisms in the TNF-alpha and TNF-receptor genes in patients with coronary artery disease

Nonlinear Dynamics of TNFR1 and TNFR2 Expression on Immune Cells: Genetic and Age-Related Aspects of Inflamm-Aging Mechanisms

Introduction: Immunosenescence alters TNF receptor expression (TNFR1 and TNFR2), contributing to chronic inflammation (inflamm-aging) and age-related diseases. Polymorphisms in TNFRSF1A and TNFRSF1B may influence receptor expression; however, their role in age-dependent modulation remains unclear. This study examines TNFR1/TNFR2 expression dynamics on T cells, B cells, and monocytes across different ages and evaluates the impact of genetic polymorphisms. Methods: PBMCs from 150 donors (18-60 years) were isolated via density-gradient centrifugation and cultured under spontaneous and LPS-stimulated conditions. TNFR1 and TNFR2 expression on immune cell subsets was quantified using flow cytometry with BD QuantiBRITE PE beads. SNP genotyping in TNFRSF1A and TNFRSF1B was performed via PCR with restriction analysis. Nonlinear age-related trends were assessed using polynomial approximation and inflection point analysis (Tukey's method). Results: Among the 23 analyzed TNF system parameters, the proportion of TNFR2+CD3+ T cells increased with age, whereas TNFR1+ and TNFR2+ monocyte populations showed significant negative correlations (p < 0.05). Inflection points (~27, 34-36, and 44-45 years) indicated nonlinear dynamics in TNFRs expression during aging. TNFR2 expression on T cells gradually increased and stabilized at later ages, whereas TNFR1 and TNFR2 expression on monocytes followed distinct declining trajectories. Genetic polymorphisms influenced correlation strength, but did not alter direction, demonstrating a conserved pattern of age-related receptor expression shifts. Conclusions: TNFR expression exhibits nonlinear, age-dependent alterations across immune cells, shaped by immunosenescence and genetic variability. The identified critical age intervals represent key phases of immune remodeling, where assessing TNFR expression may provide insights into inflamm-aging mechanisms and potential targets for immune modulation.

Targeting cytokines and immune checkpoints in atherosclerosis with monoclonal antibodies

Over the past fifteen years, treatments using monoclonal antibodies specifically targeting cytokines have been developed to treat chronic inflammatory diseases, including rheumatoid arthritis or psoriasis, both associated with increased cardiovascular risk. The cardiovascular impact of these therapies allows us to validate the clinical relevance of the knowledge acquired from experimental studies about the role of cytokines in atherosclerosis. Several clinical studies have confirmed the protective effects of anti-TNFα and anti-IL-6R monoclonal antibodies against athero-thrombotic cardiovascular risk in patients with chronic inflammatory diseases. Yet, caution is needed since anti-TNFα treatment can aggravate chronic heart failure. More recently, the CANTOS study showed for the first time that an anti-inflammatory treatment using anti-IL-1β monoclonal antibody in coronary artery disease patients significantly reduced cardiovascular events. The effects of IL-23/IL-17 axis blockade on cardiovascular risk in patients with psoriasis or arthritis remain controversial. Several monoclonal antibodies targeting costimulatory molecules have also been developed, a direct way to confirm their involvement in atherothrombotic cardiovascular diseases. Blocking the CD28^-CD80/86 axis with Abatacept has been shown to reduce cardiovascular risk. In contrast, the treatment of cancer patients with antibodies blocking immune checkpoint inhibitory receptors, such as CTLA-4, PD1, or PDL1, could worsen the risk of atherothrombotic events. In the future, cardiologists will be increasingly solicited to assess the cardiovascular risk of patients suffering from chronic inflammatory diseases or cancer and participate in choosing the most appropriate treatment. At the same time, immunomodulatory approaches directly targeting cardiovascular diseases will be developed as a complement to the usual treatment strategies.

The Association of IL-6, TNFα and CRP Gene Polymorphisms with Coronary Artery Disease in a Tunisian Population: A Case-Control study

Coronary artery disease is an inflammatory disease. Systemic markers of inflammation such as Interleukin-6, Tumor Necrosis Factor alpha and C-reactive protein have previously been shown to be associated with increased risk of cardiovascular events. The aim of the present study is to assess the role of variants in the IL-6 (- 174 G/C), TNFα (- 308 A/G) and CRP (+ 1059G/C) genes as susceptibility markers for CAD in a Tunisian population. The investigation was conducted as a case-control study involving 204 patients and 400 age-gender matched controls. Genotyping was performed using polymerase chain reaction and restriction fragment length polymorphism analysis. There are significant differences between CAD patients and the control group with regard to BMI (p < 10^-3) and family history of CAD (p < 10^-3). The CAD patients are more likely to have a history of smoking (p < 10^-3), have a higher value of TC (p = 0.003), LDLc (p = 0.016), hs-CRP (p = 0.01), IL6 (p < 10^-3) and TNFα (p = 0.038). Our analysis showed significant differences between cases and controls in genotypic distribution of IL6-174CC (p = 0.003; OR = 7.71 CI (1.58-37.56)), TNFα - 308 AA (p = 0.004; OR = 2.95 (1.57-5.51)) and CRP + 1059 CC (p < 10^-3; OR = 5.40 (2.30-12.68)). However, we failed to find an association between the different genotypes and the inflammatory markers levels. Our results suggest that the presence of IL-6 (- 174 G/C), TNFα (-308 A/G) and CRP (+ 1059G/C) polymorphisms, may be considered to be a risk factor for CAD in Tunisian population.

Inflammation and cardiovascular disease: From mechanisms to therapeutics

Inflammation constitutes a complex, highly conserved cascade of molecular and cellular events. Inflammation has been labeled as “the fire within,” is highly regulated, and is critical to host defense and tissue repair. In general, inflammation is beneficial and has evolved to promote survival. However, inflammation can also be maladaptive when chronically activated and sustained, leading to progressive tissue injury and reduced survival. Examples of a maladaptive response include rheumatologic disease and atherosclerosis. Despite evidence gathered by Virchow over 100 years ago showing that inflammatory white cells play a role in atherogenesis, atherosclerosis was until recently viewed as a disease of passive cholesterol accumulation in the subendothelial space. This view has been supplanted by considerable basic scientific and clinical evidence demonstrating that every step of atherogenesis, from the development of endothelial cell dysfunction to foam cell formation, plaque formation and progression, and ultimately plaque rupture stemming from architectural instability, is driven by the cytokines, interleukins, and cellular constituents of the inflammatory response. Herein we provide an overview of the role of inflammation in atherosclerotic cardiovascular disease, discuss the predictive value of various biomarkers involved in inflammation, and summarize recent clinical trials that evaluated the capacity of various pharmacologic interventions to attenuate the intensity of inflammation and impact risk for acute cardiovascular events.

[Polymorphic locus rs1061624 of the ТNFR2 gene is associated with the development of arterial hypertension in males]

Aim To study the involvement of cytokine polymorphous loci in development of arterial hypertension (AH) in men from the Central Black Earth region of Russia.Materials and methods 821 men were evaluated, including 564 patients with AH and 257 individuals of the control group. Analysis of 8 cytokine mononucleotide polymorphisms (MNP) was performed using the real-time polymerase chain reaction with TagMan probes. Statistical analysis was performed with the STATISTICA (v.10.0) and PLINK (v.1.06) software. The regulatory potential of MNP was analyzed with the HaploReg (v.4.1) service (http://archive.broadinstitute.org).Results The rs1061624 ТNFR2 polymorphous locus was associated with development of AH in men in recessive (odd ratio (OR), 0.33; 95 % confidence interval (CI): 0.18-0.61, рperm=0.0004) and additive (OR, 0.50, 95 % CI: 0.34-0.74, рperm=0.0006) genetic models and exerted a protective effect in development of AH. The rs1061624 MNP of the ТNFR2 gene has a regulatory significance; it is located in the DNA sites hypersensitive to the action of DNAase 1 and in binding sites for transcriptional factors and histones that mark enhancers and promoters in different organs and tissues.Conclusion The rs1061624 ТNFR2 gene polymorphism is involved in the development of AH in men of the Central Black Earth region of Russia.

Systematic review and meta-analysis of association of polymorphisms in inflammatory cytokine genes with coronary artery disease

BACKGROUND

It has comprehensively been acknowledged that a genetic contribution, especially in immune inflammatory players, such as interleukin (IL)-6 and tumor necrosis factor (TNF)-α, are critically involved in the pathophysiology of coronary artery disease (CAD). This meta-analysis study aimed to reach a conclusive understanding of the role of genetic polymorphisms, including IL6 gene C572G (rs1800796) and G174C (rs1800795) as well as TNFA gene G238A (rs361525) and G308A (rs1800629) in susceptibility to CAD.

METHODS

Two major databases, namely MEDLINE and Scopus, were searched to find the studies surveying the mentioned polymorphisms and CAD susceptibility up to July 2020. Association comparison between the polymorphisms and CAD susceptibility were assessed using pooled odds ratio (OR) and their corresponding 95% confidence interval (CI).

RESULTS

This meta-analysis study was conducted on 69 papers (73 population studies), comprising 5062 patients and 8446 controls for IL6 gene rs1800796 (17 studies), 13801 patients and 16215 controls for IL6 gene rs1800795 (38 studies), 1439 patients and 2850 controls for TNFA gene rs361525 (5 studies), and 5051 patients and 3958 controls for TNFA gene rs1800629 (13 studies), according to inclusion and exclusion criteria. There were statistically positive association between all genetic comparisons of IL6 gene rs1800795 polymorphism and the CAD risk. Moreover, the recessive model (CC vs. CG + GG) in IL6 gene rs1800796 polymorphism had marginally significant association with decreased risk of CAD. None of the TNFA gene polymorphisms were associated with CAD risk.

CONCLUSIONS

The meta-analysis revealed the positive association of IL6 gene rs1800795 polymorphism in susceptibility to CAD.

Association of tumor necrosis factor-α gene polymorphisms and coronary artery disease susceptibility: a systematic review and meta-analysis

Background

The goal of this study was to review relevant case-control studies to determine the association of tumor necrosis factor-α (TNF-α) gene polymorphisms and coronary artery disease (CAD) susceptibility.

Methods

Using appropriate keywords, we identified relevant studies using PubMed, Cochrane, Embase, CNKI, VANFUN, and VIP. Key pertinent sources in the literature were also reviewed, and all articles published through April 2019 were considered for inclusion. Based on eligible studies, we performed a meta-analysis of association between 308G/A, 238G/A, 857C/T, 863C/A and 1031 T/C polymorphisms in TNF-α and risk of CAD.

Results

We found 25 studies that were consistent with this meta-analysis, including 7697 patients in the CAD group and 9655 control patients. TNF-α 308G/A locus A showed no significant association with CAD susceptibility by the five models in the analysis of the overall population, European, African, South Asian, and North Asian patients. TNF-α 863C/A locus A and 1031 T/C locus C exhibited no significant association with CAD susceptibility. TNF-α 238G/A locus A had no significant association with CAD susceptibility in the overall population. However, TNF-α 238G/A locus A showed significant association with higher CAD susceptibility in the subgroup of Europeans and north Asians. TNF-α 857C/T locus T had no significant association with CAD susceptibility in the analysis of the overall population and Europeans. In the north Asian population, TNF-α 857C/T locus T was associated with lower CAD susceptibility by the heterozygote model.

Conclusion

TNF-α 308G/A, 857C/T, 863C/A, and 1031 T/C has no significant association with CAD susceptibility. TNF-α 238G/A locus A has significant association with CAD susceptibility in Europeans and north Asians, but has no significant association in the overall population. Studies with a larger sample size are required to confirm the association between TNF-α 238G/A and CAD susceptibility.

Tumor necrosis factor-alpha gene polymorphisms and susceptibility to ischemic heart disease: A systematic review and meta-analysis

BACKGROUND

A number of studies had reported the association between tumor necrosis factor-alpha (TNF-α) gene polymorphisms and ischemic heart disease (IHD) risk. However, the results remained controversial. Therefore, we performed a systematic review with multiple meta-analyses to provide the more precise estimations of the relationship.

METHODS

We systematically searched electronic databases (PubMed, the Web of Science, EMBASE, Medline, Chinese National Knowledge Infrastructure, WanFang and ChongQing VIP Database) for relevant studies published up to February 2017. The odds ratios (ORs) and 95% confidence intervals (CIs) were estimated for assessing the association. The present meta-analysis was performed using STATA 12.0 software.

RESULTS

In total, 45 articles with 17,375 cases and 15,375 controls involved were included. Pooled ORs revealed a significant association between TNF-α -308G/A gene polymorphism and IHD (A vs. G: OR = 1.22, 95% CI = 1.10-1.35; (AA + GA) vs. GG: OR = 1.18, 95% CI = 1.03-1.36; (AA vs. (GA+GG): OR = 1.37, 95% CI = 1.08-1.75)), indicating that the TNF-α -308A allele might be an important risk factor for IHD. No association between other TNF-α gene polymorphisms and susceptibility to IHD were observed. No publication bias were found. Sensitivity analyses indicated that our results were stable.

CONCLUSION

The present study indicated a possible association between the TNF-α -308G/A gene polymorphism and IHD risk. However, evidence was limited to confirm the role of TNF-α -238G/A, -857C/T, -863C/A, -1031T/C and other TNF-α gene polymorphisms in the risk of IHD.

Association of tumor necrosis factor-α -308 G/A gene polymorphism with coronary artery diseases: An evidence-based study

BACKGROUND

Coronary artery disease (CAD) is the leading cause of death worldwide and remains a major health problem, providing the rationale for identification of molecular markers for detection of individuals at high risk of developing CAD. Tumor necrosis factor-α (TNF-α) plays a crucial role in the pathogenesis of CAD. We have therefore explored the association of TNF-α 308 (G/A) gene polymorphism in 903 individuals with/without CAD.

METHODS

TNF-α 308 gene polymorphism was analyzed in 903 subjects of whom 222 were healthy controls. Among the 681 patients who were investigated angiographically, 468 had ≧50% stenosis and 213 patients had <50% stenosis. Biochemical profiles (eg, triglycerides, high-density lipoprotein cholesterol, low-density lipoprotein cholesterol, fasting blood glucose, and CRP) were evaluated. Associations between TNF-α genotypes with biochemical and anthropometric characteristics were determined.

RESULTS

The frequencies of TNF-α-AA or AG genotypes were significantly lower in patients classified as CAD patients with ≥ or <50% obstruction in at least one coronary artery, compared to the control group. We observed that CAD patients with ≥50% stenosis and with AA genotype were associated with higher risk of CAD with OR of 3.56 (95%CI: 1.02-12.41; P=.046) using multivariate analysis. Moreover, we found that TNF-α-308-AA genotype was associated with blood pressure and CRP level in CAD patients, compared to the wild type-genotype.

CONCLUSION

Our data showed an association of TNF-α-308G/A polymorphism with CAD patients with ≥50% obstruction, supporting the need for further investigations on the role of TNF-α-308G/A polymorphism with hypertension.

Gene polymorphisms associated with non-alcoholic fatty liver disease and coronary artery disease: a concise review

Non-alcoholic fatty liver disease (NAFLD) is a common chronic liver disease which represents a wide spectrum of hepatic damage. Several studies have reported that NAFLD is a strong independent risk factor for coronary artery disease (CAD). And patients with NAFLD are at higher risk and suggested undergoperiodic cardiovascular risk assessment. Cardiovascular disease (CVD) is responsible for the main cause of death in patients with NAFLD, and is mostly influenced by genetic factors. Both NAFLD and CAD are heterogeneous disease. Common pathways involved in the pathogenesis of NAFLD and CAD includes insulin resistance (IR), atherogenic dyslipidemia, subclinical inflammation, oxidative stress, etc. Genomic characteristics of these two diseases have been widely studied, further research about the association of these two diseases draws attention. The gene polymorphisms of adiponectin-encoding gene (ADIPOQ), leptin receptor (LEPR), apolipoprotein C3 (APOC3), peroxisome proliferator-activated receptors (PPAR), sterol regulatory elementbinding proteins (SREBP), transmembrane 6 superfamily member 2 (TM6SF2), microsomal triglyceride transfer protein (MTTP), tumor necrosis factors-alpha (TNF-α) and manganese superoxide dismutase (MnSOD) have been reported to be related to NAFLD and CAD. In this review, we aimed to provide an overview of recent insights into the genetic basis of NAFLD and CAD.

Meta-Analysis on the Correlation Between APOM rs805296 Polymorphism and Risk of Coronary Artery Disease

BACKGROUND

The present meta-analysis aimed to summarize the inconsistent findings on the association of apolipoprotein M gene (ApoM) rs805296 polymorphism with the risk of coronary artery disease (CAD), and to obtain a more authentic result about this topic.

MATERIAL/METHODS

A total of 7 available articles were identified through electronic databases--PubMed, EMBASE, and Chinese National Knowledge Infrastructure (CNKI)--and their useful data were carefully extracted. The relationship between ApoM rs805296 polymorphism and CAD risk was assessed by odds ratios (ORs) and corresponding 95% confidence intervals (95% CIs), which were calculated using the fixed- or random-effects model, according to the degree of heterogeneity. Hardy-Weinberg equilibrium test, sensitivity test, and publication bias examination were also performed in this meta-analysis.

RESULTS

According to the pooled results, ApoM rs805296 polymorphism conferred an increased risk of CAD under all the genetic contrasts: CC versus TT, CC + TC versus TT, CC versus TT+TC, C versus T, and TC versus TT (OR=2.13, 95% CI=1.16-3.91; OR=1.80, 95% CI=1.50-2.17; OR=1.91, 95% CI=1.04-3.51; OR=1.72, 95% CI=1.45-2.04; OR=1.78, 95% CI=1.47-2.15).

CONCLUSIONS

ApoM rs805296 polymorphism may be a risk factor for developing CAD.

The tumor necrosis factor-α -238G/A and IL-6 -572G/C gene polymorphisms and the risk of idiopathic dilated cardiomyopathy: a meta-analysis of 25 studies including 9493 cases and 13,971 controls

BACKGROUND

Inflammation plays an imperative role in the etiology of cardiovascular diseases (CVD). The role of cytokines in the development and progression of idiopathic dilated cardiomyopathy (IDCM) is still uncertain. The current study was conducted to evaluate the association of tumor necrosis factor-α (TNF-α) -238G/A and IL-6 -572G/C gene polymorphism with IDCM in a Pakistani population.

METHODS

IDCM cases (n=250) and healthy controls (n=300) were genotyped using PCR-RFLP.

RESULTS

The variant genotypes of both the loci showed significant differences between patients and controls (p<0.05). However, -238G/A polymorphism did not show association with the disease in the presence of covariates. We also conducted a meta-analysis of both the loci with regards to CVD in accordance with the Prisma checklist. No significant relation of the TNF-α -238G/A polymorphism with CVD was found; however, this single nucleotide polymorphism (SNP) showed an association with the disease in the Asian population after subgroup analysis (p=0.01). Whereas, the IL-6 -572G/C polymorphism showed that the variant genotype (GC+CC) was associated with higher risk of CVD in contrast to the GG genotype. Furthermore, subgroup meta-analysis demonstrated a significant association of the -572 polymorphism with CVD in Asians, but no association was observed among Western populations with this SNP.

CONCLUSIONS

Our findings support an association between the IL-6 -572G/C polymorphism and IDCM risk. The role of the TNF-α -238G/A polymorphism in IDCM is still unclear. Further studies are warranted to determine the serum cytokine levels in relation to the cytokines' SNP in diverse ethnic groups to ascertain the molecular basis of the disease pathology.

Integrated probability of coronary heart disease subject to the -308 tumor necrosis factor-alpha SNP: a Bayesian meta-analysis

We present a meta-analysis of independent studies on the potential implication in the occurrence of coronary heart disease (CHD) of the single-nucleotide polymorphism (SNP) at the −308 position of the tumor necrosis factor alpha (TNF-alpha) gene. We use Bayesian analysis to integrate independent data sets and to infer statistically robust measurements of correlation. Bayesian hypothesis testing indicates that there is no preference for the hypothesis that the −308 TNF-alpha SNP is related to the occurrence of CHD, in the Caucasian or in the Asian population, over the null hypothesis. As a measure of correlation, we use the probability of occurrence of CHD conditional on the presence of the SNP, derived as the posterior probability of the Bayesian meta-analysis. The conditional probability indicates that CHD is not more likely to occur when the SNP is present, which suggests that the −308 TNF-alpha SNP is not implicated in the occurrence of CHD.

Tumor necrosis factor-alpha G-238A polymorphism and coronary artery disease risk: a meta-analysis of 4,222 patients and 4,832 controls

BACKGROUND

The aim of the present study was to investigate the association between tumor necrosis factor-alpha (TNF-α) gene G-238A polymorphism and risk of coronary artery disease (CAD) using a meta-analytical approach.

METHODS

The PubMed and Embase databases were searched for relevant publications up to January 13, 2015. Four authors (XPH, XDZ, XTZ, and ZJZ) independently selected the studies, extracted, and analyzed the data using the Comprehensive Meta-Analysis software. The sensitivity and subgroups analyses were also performed. Either a fixed effects or a random effects model was used to estimate pooled odds ratios (ORs) and their 95% confidence intervals (CIs).

RESULTS

Finally, ten articles including eleven case-control studies involving 4,222 patients and 4,832 controls were yielded. The results indicated no significant association between G-238A polymorphism and CAD risk (A vs G: OR =1.08, 95% CI =0.89-1.30; AA vs GG: OR =1.15, 95% CI =0.59-2.25; GA vs GG: OR =1.14, 95% CI =0.88-1.48; AA vs [GG + GA]: OR =1.09, 95% CI =0.56-2.14; (GA + AA) vs GG: OR =1.11, 95% CI =0.90-1.38). In the subgroup analyses, similar results were obtained with overall populations. The sensitivity analyses showed that the overall results were robust. No publication bias was detected.

CONCLUSION

Based on current evidence, we can conclude that TNF-α G-238A polymorphism might not be associated with CAD risk.

Association of Tumor Necrosis Factor-alpha Polymorphisms and Risk of Coronary Artery Disease in Patients With Non-alcoholic Fatty Liver Disease

BACKGROUND

Cardiovascular events account for the main cause of death in patients with non-alcoholic fatty liver disease (NAFLD), and are largely influenced by genetic factors. Although multiple studies showed that tumor necrosis factor-alpha (TNF-α) polymorphisms are risk factors in the progression of NAFLD, few papers on the association of the polymorphisms and the developing coronary artery disease (CAD) in NAFLD patients have been reported.

OBJECTIVES

The present study was designed to evaluate the association of TNF-α polymorphisms at residues -238 and -308, with the risk of developing CAD in Chinese patients with NAFLD.

PATIENTS AND METHODS

The TNF-α polymorphisms at residues 238 and 308 were genotyped in B-type ultrasonography proven NAFLD patients with (n = 246), without (n = 247) CAD and healthy controls (n = 304), using polymerase chain reaction (PCR). Serum lipid profiles were determined using biochemical methods. Statistical analyses were performed using SPSS statistical software, version 20.0 for Mac.

RESULTS

We found a significant association between TNF-α-238 guanine to alanine (GA) polymorphism and carriers of variant allele A between NAFLD patients with and without CAD (P < 0.05). Carriers of the A allele of TNF-α-238 had higher serum triglycerides (TG) and low density lipoprotein (LDL) levels in NAFLD patients with CAD (P = 0.025 and 0.001, respectively) and a higher TG level in NAFLD patients without CAD (P = 0.017), than their non-carrier counterparts.

CONCLUSIONS

In the Chinese Han population that we studied, NAFLD patients who carry the TNF-α-238 GA polymorphism have an increased risk of developing CAD. Mechanisms underlying this potentially important association require further investigation.

TNF-alpha-308G>A polymorphism and the risk of familial CAD in a Pakistani population

A case-control and trio-families study was performed to establish a potential association between TNF-alpha gene promoter SNPs at -308 and -238, and occurrence of CAD in a Pakistani population. In the first phase, 150 patients and 150 controls were enrolled in the case-control association study. In the second phase, heritability of susceptible alleles was investigated from 88 trio-families with CAD affected offspring. Biochemical analysis of lipids and hs-CRP was carried out spectrophotometrically, while serum TNF-alpha concentrations were determined by enzyme-linked immunosorbent assay. Genotyping of the TNF-alpha SNPs were determined by PCR-RFLP method. Elevated serum TNF-alpha and hs-CRP were observed from CAD vs. controls (P<0.0001; for both). The evaluation of TNF-alpha-308G>A polymorphism in case-control study revealed that the said SNP was significantly associated with the increased risk of CAD. The findings demonstrated a significant link between the TNF-alpha variant allele A at -308 and CAD (P=0.0035), whereas the -238 SNP was not associated with the disease. Haplotype A-G of the TNF-alpha gene at -308G>A and -238G>A showed higher frequency in the patient group compared with controls (P<0.05). Moreover, data showed preferential transmission of the disease susceptible allele A at TNF-alpha-308 from parent to affected offspring in a trio-family study (P<0.0001). The current research leads to conclusion that the TNF-alpha-308G>A polymorphism is associated with CAD in the study population. Furthermore, for the first time, we showed that the TNF-alpha-308A allele was significantly associated with the familial CAD in our high risk population.

TNF-α, IL-6, and IL-8 cytokines and their association with TNF-α-308 G/A polymorphism and postoperative sepsis

INTRODUCTION

Early prediction of postoperative sepsis remains an enormous clinical challenge. Association of TNF-α-308 G/A polymorphism with sepsis remains controversial. We, therefore, investigated this polymorphism with serum levels of cytokines TNF-α, IL-6, and IL-8 in relation to development of sepsis following major gastrointestinal surgery.

METHODS

Two hundred and thirty-nine patients undergoing major gastrointestinal surgery were enrolled. Polymorphism was studied through the analysis of restriction fragments of Nco1-digested DNA with the polymerase chain reaction. All patients were followed for 1 month following surgery for evidence of sepsis. Levels of serum cytokines TNF-α, IL-6, and IL-8 were measured preoperatively and postoperatively by enzyme-linked immunosorbent assay (ELISA).

RESULTS

Forty-seven (19.66 %) patients developed postoperative sepsis. Patients with postoperative sepsis were significantly (p = 0.002) more likely to possess AA homozygous genotype with higher capacity to produce cytokines TNF-α (p < 0.0001), IL-6 (p < 0.0001), and IL-8 (p < 0.0001) as compared to other genotypes. When compared with patients carrying at least one G allele, the AA genotype was associated with a significantly higher probability (odds ratio (OR) = 4.17; p = 0.003; 95 % confidence interval (CI) = 1.5-11.48) of developing sepsis. Compared with the GG genotype, AA was associated with a significantly higher probability (OR = 5.18; p = 0.0008; 95 % CI = 1.82-14.76) of sepsis development.

CONCLUSION

TNF-α-308 G/A polymorphism is significantly associated with the development of postoperative sepsis and with increased expression of cytokines TNF-α, IL-6, and IL-8.

Polymorphisms in the tumor necrosis factor receptor genes affect the expression levels of membrane-bound type I and type II receptors

The level of TNF receptors on various cells of immune system and its association with the gene polymorphism were investigated. Determining the levels of membrane-bound TNFα receptors on peripheral blood mononuclear cells (PBMCs) was performed by flow cytometry using BD QuantiBRITE calibration particles. Soluble TNFα receptor (sTNFRs) levels were determined by ELISA and genotyping was determined by PCR-RFLP. Homozygous TT individuals at SNP −609G/T TNFRI (rs4149570) showed lower levels of sTNFRI compared to GG genotype carriers. Homozygous carriers of CC genotype at SNP −1207G/C TNFRI (rs4149569) had lower expression densities of membrane-bound TNFRI on intact CD14⁺ monocytes compared to individuals with the GC genotype. The frequency differences in the CD3⁺ and CD19⁺ cells expressing TNFRII in relation to SNP −1709A/T TNFRII (rs652625) in healthy individuals were also determined. The genotype CC in SNP −3609C/T TNFRII (rs590368) was associated with a lower percentage of CD14⁺ cells expressing TNFRII compared to individuals with the CT genotype. Patients with rheumatoid arthritis had no significant changes in the frequencies of genotypes. Reduced frequency was identified for the combination TNFRI −609GT + TNFRII −3609CC only. The polymorphisms in genes represent one of cell type-specific mechanisms affecting the expression levels of membrane-bound TNFα receptors and TNFα-mediated signaling.

Tumor Necrosis Factor-α Gene Polymorphism Correlates with Cardiovascular Disease in Patients with End-Stage Renal Disease

BACKGROUND AND OBJECTIVE

Tumor necrosis factor-alpha (TNFalpha) is a potent proinflammatory cytokine. Through its effects on lipid metabolism and endothelial function, TNFalpha is involved in cardiovascular disease (CVD). We have studied two polymorphisms in the promoter region of the TNFalpha gene (TNF -308G/A and TNF -238G/A) in end-stage renal disease (ESRD) patients with and without CVD. The aim was to assess the association of these polymorphisms with ESRD and cardiovascular comorbidity in hemodialyzed patients.

METHODS

A total of 603 patients with ESRD treated with hemodialysis (382 patients with CVD) and 325 healthy control subjects were genotyped for the TNF -308G/A and TNF -238G/A ploymorphisms by the polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) procedure.

RESULTS

The A allele of the TNF -308 polymorphism was more frequent in the ESRD group than in control individuals. The odds ratio (OR) for the risk allele was 2.05 (95% CI 1.48, 2.84). In the subgroup of ESRD patients with CVD, the OR was 5.76 (95% CI 3.67, 9.03) relative to ESRD patients without CVD. There was no association observed between the TNF -238 polymorphism and renal failure or CVD in ESRD patients.

CONCLUSION

Our results demonstrate for the first time that the A allele of the TNF -308 polymorphism is associated with CVD in hemodialyzed ESRD patients. If confirmed in prospective studies, it may be a predictor of increased susceptibility to CVD in these patients.

A review of genetic association studies of obstructive sleep apnea: field synopsis and meta-analysis

STUDY OBJECTIVES

Obstructive sleep apnea (OSA) is a multifactorial disorder with a heritable component. We performed a field synopsis of genetic association studies of OSA to synthesize the available evidence.

DESIGN

Systematic literature review and meta-analysis.

SETTING

Genetic association studies.

PATIENTS OR PARTICIPANTS

We searched multiple databases to identify studies of non-HLA genetic associations in OSA. We assessed the power of the primary studies to identify odds ratios (OR) in a plausible range and performed random effects meta-analyses for genetic associations investigated by at least 3 studies. We explored the consistency of the findings between population- and family-based studies.

INTERVENTIONS

None

MEASUREMENTS AND RESULTS

We identified a total of 31 population-based case-control studies reporting allele-frequency data on 48 polymorphism-OSA associations. Sample sizes were generally small (median number of cases = 102, 25th-75th percentile = 55-151; median number of controls = 79, 25th-75th percentile = 58-137), and genetic effects were moderate in magnitude (median OR = 1.15, 25th-75th percentile = 0.89-1.40). Studies were severely underpowered to detect ORs as high as 2; only eight comparisons (in 6 studies) had more than 90% power to identify a genetic effect of that magnitude at its current sample size. Four genetic associations had been investigated in ≥ 3 studies: TNFA (-308 A/G) rs1800629, ACE I/D, APOE ε2, and APOE ε4. Only TNFA rs1800629 was significantly associated with OSA under an allele frequency model (3 studies, odds ratio [OR] = 1.82, 95% confidence interval [CI] 1.26-2.61). These results were robust to alternative genetic models; findings for APOE variants were consistent with those from family-based studies.

CONCLUSIONS

The developing field of OSA genetics is currently dominated by small and underpowered investigations. Promising findings regarding TNFA rs1800629 need to be replicated in larger studies using more comprehensive genotyping methods.

Tumor necrosis factor-alpha G-308A gene polymorphism and coronary heart disease susceptibility: an updated meta-analysis

PURPOSE

Several studies have reported apparently conflicting findings for the effects of tumor necrosis factor-alpha (TNF-α) G-308A polymorphism on coronary heart disease (CHD) susceptibility. We undertook a systematic review and meta-analysis to investigate the association between this gene variant and CHD predisposition.

METHODS

We systematically searched electronic databases (Medline, EMbase, Chinese BioMedical, BIOSIS, Global Health, PsycINFO, Allied and Complementary Medicine Database, Cochrane Library, HuGE Navigator, and British Nursing) for relevant studies published between 1947 and October, 2010. Summarized estimation of odds ratio (OR) and 95% confidence interval (CI) were calculated. Publication bias and heterogeneity among studies were explored.

RESULTS

We identified 24 studies providing data for 9 921 cases and 7 944 controls. Pooled analysis based on ORs adjusted by CHD risk factors showed that carrying the TNF-α gene A variant conferred a 1.5-fold increased risk of developing CHD (AG+AA vs. GG, OR = 1.50, 95% CI: 1.23-1.77) in Caucasian population. No significant association between the gene polymorphism and CHD risk could be found in other ethnic groups.

CONCLUSIONS

It is probable that carrying the A variant is associated with CHD risk in Caucasians but not in Asians, Indians, or Africans. Further studies are merited to assess the association in greater details, especially in Asians, Indians and Africans.

Tumor necrosis factor-α: investigation of gene polymorphism and regulation of TACE-TNF-α system in patients with acute myocardial infarction

A polymorphism within tumor necrosis factor-α (TNF-α) gene promoter and contribution of TNF-α converting enzyme (TACE) have been reported to be associated with TNF-α production which may increase susceptibility to heart failure such as acute myocardial infarction (AMI). However, the relationship between this polymorphism and susceptibility to AMI and the mechanism of TACE-TNF-α system regulation has poorly been studied. Genomic DNA and peripheral blood mononuclear cells (PBMCs) of patients with AMI and control subjects was extracted. The -308 G/A TNF-α polymorphism was detected. The mRNA transcription and protein expression levels of TNF-α and TACE were analyzed by real time RT-PCR and flow cytometry respectively as well as plasma TNF-α by ELISA. The 'A' allele frequency of TNF-α was significantly more frequent in the patients than controls (P < 0.001). There were statistically significant differences in TNF-α and TACE mRNA and protein levels as well as circulating TNF-α in the patients. However, these levels were higher in the patients who carry 'A' allele. There were significant positive correlation between these mRNAs and protein expression levels (r = 0.66, P < 0.001, r = 0.78, P < 0.001 respectively). These data suggest that genetic polymorphism in TNF-α might be helpful for determining susceptibility to AMI in Iranian patients. The TACE-TNF-α system in circulating leucocytes is stimulated which these results demonstrate that in patients with AMI, TACE expression in PBMC increases with TNF-α expression and processing of TNF-α in PBMC might be regulated by TACE at transcriptional, translational, and post-translational levels in AMI.

Implications of genetic polymorphisms in inflammation-induced atherosclerosis

Inflammation is the mainstay of atherosclerosis and is an important governing factor at all stages of the disease process from lesion formation to plaque build-up and final end-stage rupture and thrombosis. An overview of the numerous clinico-epidemiological studies on the association between inflammatory gene polymorphisms and Cardiovascular disease (CVD) and its co-morbidities have shown that the risk associated with any single genotype is modest while the haplotypes, especially those defined on the basis of tag-SNP approach, have better coverage of the gene and show moderately higher impact on disease risk. Nevertheless, even these associations have been inconsistent with low cross-race repeatability. This has been attributed to many plausible causes such as clinical heterogeneity, sample selection criteria, variable genetic landscapes across different ethnic groups, confounding effect of co-morbidities etc. On the other hand, unbiased studies such as the family-based linkage and case-control based associations that have taken into account, thousands of genotypic markers spanning the whole genome, have had the ability to identify novel genetic loci for coronary artery disease. These studies have shown that many inflammatory genes are involved in the regulation of specific biomarkers of inflammation that collectively contribute to the disease-associated risk. In addition, there appears to be considerable cross talk between the different biochemical and metabolic processes. Therefore, consideration of all these factors can build towards an 'atherosclerotic bionetwork' that can refine our quest for developing a robust risk stratification tool for cardiovascular disease.

Determination of single-nucleotide polymorphism in the proximal promoter region of apolipoprotein M gene in coronary artery diseases

OBJECTIVE

It has been reported that single-nucleotide polymorphism (SNP) in the proximal promoter region of apolipoprotein M (apoM) gene may confer the risk in the development of type 2 diabetes (T2D) and coronary artery disease (CAD) in the Han Chinese. However, in a recent study demonstrated that plasma apoM level did not correlated to the coronary heart disease. In the present studies, we investigated the SNP T-778C of apoM gene in CAD patients and controls in the Han Chinese population. Moreover we examined whether serum apoM levels could be influenced by this promoter mutation.

MATERIAL AND METHODS

One hundred twenty-six CAD patients and 118 non-CAD patients were subjected in the present study. All patients were confirmed by the angiography. The genotyping of polymorphisms T-778C in apoM promoter was determined by real-time polymerase chain reaction. Serum apoM levels were semi-quantitatively determined by the dot-blotting analysis.

RESULTS

Distribution of apoM T-778C genotype in non-CAD patients was as following: 84.7% were T/T, 15.3% were T/C and 0.0% was C/C. T allele frequencies were 92.4% and C allele, 7.6%. In the CAD patients, 99 patients (78.6%) had the T/T genotype, 25 patients (19.8%) with T/C genotype and 2 patients (1.6%) with C/C genotype. The allele frequency was 88.5% for the T allele and 11.5% for the C allele. There was no statistical significant difference of serum apoM levels found in these three genotypes.

CONCLUSIONS

There was no significant difference in allele or genotype frequencies between CAD patients and non-CAD patients. Binary logistic regression analysis with adjustments for age, gender, triglycerides, total cholesterol, low-density lipoprotein, high-density lipoprotein, apoAI, apoB, and LP(a) indicated that the TC and CC genotypes in SNP T-778C were not significantly associated with the development of CAD (odds ratio = 1.510, 95% confidence interval: 0.756-3.017; p = 0.243).

-308G>A and -1031T>C tumor necrosis factor gene polymorphisms in Tunisian patients with coronary artery disease

BACKGROUND

Recent research has shown that inflammation plays a key role in coronary artery disease (CAD) and other manifestations of atherosclerosis. Several lines of evidence support a key role for tumor necrosis factor-alpha (TNF-alpha), a potent immunomodulator and pro-inflammatory cytokine, in the development of atherosclerosis and in complications of CAD.

METHODS

We investigated the possible association between CAD and the TNF gene promoter polymorphisms -308G>A and -1031T>C in a Tunisian population. We compared the distribution of these polymorphisms between 418 patients with CAD and 406 healthy controls using polymerase chain reaction restriction fragment length-polymorphism analysis.

RESULTS

The frequency of the TNF-alpha -308A allele in the control group was similar to that observed in CAD patients [p=0.78; odds ratio (OR)=1.15; 95% confidence interval (CI)=0.86-1.55], but higher than those described in other Europeans, such as in the French, Finnish and Spanish. Concerning the TNF-alpha -1031T/C polymorphism, the same distribution was observed between patients with CAD and controls (p=0.12; OR=1.27; 95% CI=0.94-1.72). In addition, the genotype and allele frequencies of control individuals were comparable to those previously reported in healthy Tunisian controls and other ethnic groups. Haplotype analysis (TNF-alpha -308G>A and -1031T>C) demonstrated no significant association between TNF haplotypes and CAD.

CONCLUSIONS

We conclude that TNF promoter gene polymorphisms at position -308G>A and -1031T>C do not play a major role in the pathogenesis of CAD in the Tunisian population.

Tumor necrosis factor alpha -308 gene locus promoter polymorphism: an analysis of association with health and disease

Tumor necrosis factor-alpha (TNF-alpha) is a potent immunomediator and proinflammatory cytokine that has been implicated in the pathogenesis of a large number of human diseases. The location of its gene within major histocompatibility complex and biological activities has raised the possibility that polymorphisms within this locus may contribute to the pathogenesis of wide range of autoimmune and infectious diseases. For example, a bi-allelic single nucleotide substitution of G (TNFA1 allele) with A (TNFA2 allele) polymorphism at -308 nucleotides upstream from the transcription initiation site in the TNF-alpha promoter is associated with elevated TNF-alpha levels and disease susceptibilities. However, it is still unclear whether TNF-alpha -308 polymorphism plays a part in the disease process, in particular whether it could affect transcription factor binding and in turn influence TNF-alpha transcription and synthesis. Several studies have suggested that TNFA2 allele is significantly linked with the high TNF-alpha-producing autoimmune MHC haplotype HLA-A1, B8, DR3, with elevated serum TNF-alpha levels and a more severe outcome in diseases. This review discusses the genetics of the TNF-alpha -308 polymorphism in selected major diseases and evaluates its common role in health and disease.

Association of IL23R, TNFRSF1A, and HLA-DRB1*0103 allele variants with inflammatory bowel disease phenotypes in the Finnish population

BACKGROUND

Crohn's disease (CD) and ulcerative colitis (UC), 2 major forms of inflammatory bowel disease (IBD), are complex disorders with significant genetic predisposition. The first CD-associated gene, CARD15/NOD2, was recently identified and since then several reports on novel IBD candidate genes have emerged. We investigated disease phenotype association to genetic variations in IL23R, ATG16L1, DLG5, ABCB1/MDR1, TLR4, TNFRSF1A, chromosome 5 risk haplotype including SLC22A4 and SLC22A5, and HLA-DRB1*0103 allele among Finnish IBD patients.

METHODS

A total of 699 IBD patients were genotyped for disease-associated variants by polymerase chain reaction (PCR) and restriction enzyme digestion or Sequenom iPLEX method.

RESULTS

Five markers spanning the IL23R gene were associated with CD. The SNP (single nucleotide polymorphism) rs2201841 gave the strongest association (P = 0.002). The rare HLA-DRB1*0103 allele was found to associate with UC (P = 0.008), and the TNFRSF1A A36G variant was associated with familial UC (P = 0.007). Upon phenotypic analysis we detected association between familial UC and rare TNFRSF1A alleles 36G and IVS6+10G (P = 0.001 and P = 0.042, respectively). In addition, IL23R markers were associated with stricturing CD (P = 0.010-0.017), and ileocolonic CD was more prevalent in the carriers of the same 2 TNFRSF1A variants (P = 0.021 and P = 0.028, respectively). Less significant genotype-phenotype associations were observed for the TLR4 and HLA variants.

CONCLUSIONS

We were able to replicate the association of the IL23R variants with CD as well as HLA-DRB1*0103 with UC; confirmation of TNFRSF1A association with UC needs additional studies. Our findings also suggest that polymorphisms at IL23R and TNFRSF1A, and possibly HLA and TLR4, loci may account for phenotypic variation in IBD.

Association of TNF-alpha and TNFR1 promoters and 3' UTR region of TNFR2 gene polymorphisms with genetic susceptibility to tobacco-related oral carcinoma in Asian Indians

Tobacco-related oral squamous cell carcinoma is a common malignancy in Asian people. It accounts for almost 40% of cancers among Indian men and 3% in the Western world. Smokeless tobacco has been shown to induce tumor necrosis factor-alpha (TNF-alpha), which, along with its receptors, is over-expressed in people with oral carcinoma. Single nucleotide polymorphisms (SNPs) in TNF-alpha and TNF receptor genes may affect their expression and may be a potential determinant of susceptibility to tobacco-related oral carcinomas. We assessed SNPs in TNF-alpha(-308, -238) and TNF receptor 1 (TNFR1; -609) promoters by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) and at four sites of TNF receptor 2 gene (TNFR2; exon 9 site 1176; exon 10 sites 1663, 1668 and 1690) by PCR-sequence-specific primers (PCR-SSP) techniques, respectively, in 94 patients and 130 healthy controls. TNF-alpha-308 G allele was significantly lower (Pc=0.004; OR=3.85), whereas A allele was significantly higher (Pc=0.004; OR=0.25) in patients compared with controls. No significant change was observed at -238 promoter site between the two groups. In the case of TNF receptors, both TNFR1 -609 TT (Pc=0.006; OR=15.3) and TNFR2 1690 CT (Pc=0.018; OR=5.6) genotypes were significantly lower in patients compared with controls. It seems that TNF-alpha-308 G/A may be related to susceptibility, whereas -609 TT TNFR1 and 1690 C/T TNFR2 SNPs may be protective to tobacco-related oral squamous cell carcinoma. These SNPs may be useful as a marker for high-risk groups among Asian Indians.

Association of HLA-DRB1*13 and TNF-alpha gene polymorphisms with clearance of chronic hepatitis B infection and risk of hepatocellular carcinoma in Thai population

Considerable evidence suggests that host genetic factor play an important role in the pathogenesis and clinical outcome of chronic hepatitis B virus (HBV) infection in several ethic groups. Association study was performed included 150 chronic HBV patients, 100 resolved hepatitis B and 150 healthy individuals with similar ethic background. Interestingly, human leucocyte antigen (HLA)-DR13 show a strong association with the clearance of HBV [odds ratio (OR) = 0.04, 95% confidence interval (CI) = 0.00-0.26, corrected P-value (P(c)) = 0.0008] similar to reports from several ethic groups. TNF-alpha promoter polymorphisms (-863, -308 and -238) were also analysed. Only -863 C allele was found to be significantly decreased in chronic HBV patients compared with healthy control (P(c) = 0.03, OR = 0.54, 95% CI = 0.35-0.84 respectively). This -863C allele was not in linkage disequilibrium with HLA-DR13 suggesting that other genetic markers linked with -863C might influence clearance of chronic HBV infection in Thai. When stratified chronic HBV patients into patients without hepatocellular carcinoma (HCC) and with HCC, the -863 A allele was significantly increased in the HCC group compared to healthy control (P(c) = 0.003, OR = 2.61, 95% CI = 1.49-4.60). Haplotype analysis (-863/-308/-238) revealed that the homozygosity of the haplotype (CGG/CGG) was a protective marker for HCC (OR = 0.37, 95% CI = 0.17-0.79, P(c) = 0.02). One can propose that carriers of -863A genotype are associated with increased levels of TNF-alpha in the liver in response to HBV infection and induce hapatocyte damage that may finally lead to HCC development. Additional study is needed to validate these finding and to further explore the genetic pathogenesis of HBV infection.

Involvement of -308 TNF-alpha and 1267 Hsp70-2 polymorphisms and zinc status in the susceptibility of coronary artery disease (CAD) in old patients

Coronary artery disease (CAD) is characterized by an inflammatory status and it represents the major cause of death in elderly. Zinc deficiency and inflammatory genes within major histocompatibility complex (MHC) region are implicated in ischaemic heart diseases. TNF-alpha is present in coronary artery plaques and may provoke plaque instability. Hsp70 plays instead a pro-atherogenic role, via proinflammatory cytokine production, in atherosclerotic lesions contributing to plaque rupture. Contradictory data report the association between -308 TNF-alpha polymorphism and CAD, while no investigations exist on Hsp70-2 gene in CAD. In the current study, we analysed -308 TNF-alpha and 1267 Hsp70-2 polymorphisms and zinc status in 190 healthy old controls and 216 old patients with carotid stenosis subdivided in two groups: the first one 105 patients with CAD (C group), and the second one 111 patients without cardiovascular events (D group). We found a lack of association between -308 TNF-alpha polymorphism and CAD. Conversely, 1267 Hsp70-2 polymorphism was associated with CAD. In particular, significant higher frequency of AB + BB genotypes (B + genotype) was observed in C patients than controls (71.4 vs.56.9%, P = 0.017, odds ratio = 1.898). However, when C patients were subdivided into four subgroups on the basis of presence/absence of 1267B Hsp70-2 and -308A TNF-alpha alleles, B + A + patients showed higher prothrombin activity as well as Hsp70-2, TNF-alpha, IL-6 gene expressions in carotid atheroma when compared to B - A - genotypes. The zinc status (plasma and Zn/Fe ratio in erythrocytes) is not affected by these polymorphisms. However, zinc deficiency is present in CAD condition. In conclusion, 1267 HSP70-2 polymorphism and zinc deficiency, rather than -308 TNF-alpha, are independently associated with CAD. B + A+ and B + A- carriers seem more predisposed to ischaemic events; conversely, B - A- genotype may be considered a protective marker against CAD.

A variant of position -308 of the Tumour necrosis factor alpha gene promoter and the risk of coronary heart disease

PURPOSE

The aim of this study was to investigate whether the variability between individuals with coronary heart disease (CHD) is related to the prevalence of TNF-alpha gene promoter -308 variant in un-matched British Caucasian population from East Midlands.

PROCEDURES

Genotypes and allele frequencies were determined using restriction fragment length polymorphism analysis of polymerase chain reaction (PCR) products. Genomic DNA prepared from peripheral blood leukocytes of patients (n=97) and healthy controls (n=95) demonstrated two alleles TNF*1 (G) and TNF*2 (A).

FINDINGS

The genotype distribution in patients was GG, n=59; GA, n=36; and AA, n=2 and in controls was GG, n=41; GA, n=40; and AA, n=14 (P=0.014). The association analysis demonstrated that TNF*1 allele in patients appears to be associated with greater incidences of CHD (OR 2.15; CI, 1.36-3.39; P=0.001).

CONCLUSIONS

Our results suggest that TNF*1 allele (TNF-alpha -308 GG or GA) has a high prevalence among British Caucasian population that correlates with an increased CHD risk.

Effect of the G-308A polymorphism of the tumor necrosis factor alpha gene on the risk of ischemic heart disease and ischemic stroke: a meta-analysis

BACKGROUND

Under the hypothesis that the G-308A polymorphism in the promoter region of the tumor necrosis factor alpha gene might increase tumor necrosis factor alpha expression, several investigations have been performed to examine the influence of the -308A allele on the risk of cardiovascular events. The results of these studies, however, have been conflicting. To provide a more robust estimate of the putative effect of the G-308A polymorphism on the risk of cerebrocardiovascular events, we did 2 meta-analyses that examined the role of the -308A variant in both ischemic heart disease (IHD) and ischemic stroke.

METHODS

We applied both fixed- and random-effects models to combine odds ratios (OR) and 95% CIs, and publication bias and heterogeneity were explored.

RESULTS

Data of 17,030 subjects from 23 studies were used. Overall, in populations predominantly of European ancestry, no association between the G-308A polymorphism and IHD under a dominant model (AA + GA vs GG) was observed: OR, 1.07; 95% CI, 0.94-1.21; P = .32. Similarly, the -308A allele was not associated with ischemic stroke considering all studies: OR, 0.99; 95% CI, 0.70-1.41, P = .96. However, analysis by ancestry revealed that Asian subjects harboring the -308A variant were approximately 40% less likely to have stroke compared to the GG genotype: OR, 0.62; 95% CI, 0.44-0.86; P = .004.

CONCLUSIONS

These results suggest that the G-308A polymorphism is unlikely to be associated with the development of IHD, whereas it might be a protective factor for ischemic stroke in Asians only.

GSTM1 and TNF-alpha gene polymorphisms and relations between blood lead and inflammatory markers in a non-occupational population

Inflammation is known to be an important underlying condition in the development of a variety of diseases. To investigate whether blood lead induces inflammatory reactions in non-occupationally exposed adults and the effects of genetic susceptibility associated with GSTM1 and TNF-alpha gene polymorphisms on this inflammatory response, we measured blood lead levels in 300 healthy university students. Total serum TNF-alpha and IL-6 levels and WBC counts were determined to evaluate the inflammatory response. Allelic loss of GSTM1 and the TNF-alpha-308 G>A polymorphism were determined by PCR and RFLP. Positive relations between blood lead and three inflammation biomarkers were shown in male subjects with blood lead > or =2.51microg/dl (median value) (TNF-alpha, p=0.015; IL-6, p=0.082; and WBC, p=0.044). However, subgroup analysis by genotype showed an effect of blood lead on the three biomarkers only in individuals with the GSTM1 null (TNF-alpha, p=0.020; IL-6, p=0.096; and WBC, p=0.017) or TNF-alpha GG (TNF-alpha, p=0.017; IL-6, p=0.088; and WBC, p=0.095) genotype, and not in individuals with GSTM1 present (all three inflammatory biomarkers, p>0.1) or the TNF-alpha GA or AA (all three biomarkers, p>0.1) genotype. These results suggest that blood lead affects the inflammatory response and that GSTM1 and TNF-alpha gene polymorphisms are genetic factors associated with lead-induced inflammatory response.

Present status of outcome prediction of invasive coronary treatment by using genetic markers

A growing number of studies suggest that the outcome after invasive coronary treatment may be in part genetically determined. Here, we review the present status of outcome prediction of invasive coronary treatments by using genetic markers. Although some studies found an association between one or another genetic marker with one or another clinical endpoint, many other studies found no such relations; to date, none of the genetic markers that have been investigated in association studies are used in routine clinical practice to prospectively assess the prognosis following invasive coronary treatment or to decide upon therapeutic strategies. Many associations between genetic markers and certain clinical endpoints were initially reported in small studies but could not be confirmed in larger ones. Some of these discrepancies may be explained by publication bias. Some genetic variants may have true effects on clinical endpoints, which, albeit biologically interesting, do not bear much clinical relevance. On the other hand, many-if not most-studies that have been published to date are more or less grossly underpowered and very rarely report on the results of an a priori power analysis. Thus, there is still a need for further high-quality studies designed to investigate the specific contribution of genetic factors to the outcome after invasive coronary interventions.

Common genetic vulnerability to depressive symptoms and coronary artery disease: a review and development of candidate genes related to inflammation and serotonin

OBJECTIVE

Although it is well established that depressive symptoms are associated with recurrent cardiac events among cardiac patients and novel cardiac events among participants with no known coronary artery disease (CAD), the nature of this association remains unclear. In this regard, little attention has been paid to the possibility that common genetic vulnerability contributes to both depressive symptoms and CAD. In this paper, we review the existing evidence for common genetic contributions to depression and CAD, primarily using evidence from twin and family studies, followed by a review of two major pathophysiological mechanisms thought to underlie covariation between depressive symptoms and CAD: inflammation and serotonin. We conclude with an overview of select candidate genes within these pathways.

METHODS

Literature review.

RESULTS

In twin studies, both depression and CAD appear heritable. In the only twin study to consider depression and CAD jointly, the correlation across heritabilities was 0.42, suggesting that nearly 20% of variability in depressive symptoms and CAD was attributable to common genetic factors. In addition, although it is plausible that genetic variation related to inflammation and serotonin may be associated with both depression and CAD, genetic variation related to inflammation has been primary examined in relation to CAD, whereas genetic variation in the serotonin system has been primarily examined in relation to depression.

CONCLUSIONS

It appears that the covariation of depressive symptoms and CAD may be attributable, in part, to a common genetic vulnerability. Although several pathways may be involved, genes within the inflammation and serotonin pathways may serve as good candidates for the first steps in identifying genetic variation important for depression, CAD or both.

Impact of cytokine gene polymorphism on cardiovascular risk in renal transplant recipients

Cardiovascular events are the leading causes of morbidity and mortality in renal transplant recipients (RTR). Given the role of inflammation in atherosclerosis, the contribution of functional polymorphisms of cytokines to cardiovascular diseases (CVD) was assessed in RTR in this study. Polymorphisms of tumour necrosis factor alpha (TNF-alpha) gene [-308 (G-->A), -238 (G-->A)], interleukin-10 (IL-10) gene [-1082(A-->G), -819 (T-->C), -592 (A-->C)], transforming growth factor beta 1 (TGF-beta1) gene [codon 10 (T-->C), codon 25 (G-->C)], carotis intima media thickness (CIMT), left ventricular mass index (LVMI), 24-h ambulatory blood pressure and serum lipoprotein homocysteine level, erythrocyte sedimentation rate, serum C-reactive protein (CRP) and serum fibrinogen level of RTR were determined. Seventy-two RTR (26 cadaveric allograft, 46 living-related allograft, 43 male, 29 female) were included in this study. LVMI were similar in TNF-alpha, IL-10 and TGF-beta1 genotypes. Right and left CIMT were higher in TT genotype (n = 16) than CT (n = 46) and CC (n = 10) genotypes of TGF-beta1 codon 10 (T-->C) gene polymorphism (RCIMT, 7.7 +/- 2.2 mm vs. 7.0 +/- 1.4 mm vs. 5.9 +/- 1.4 mm, P = 0.025; LCIMT, 8.5 +/- 2.5 mm vs. 7.0 +/- 1.3 mm vs. 6.1 +/- 1.2 mm, P = 0.002). Lipoprotein (a) level of TT genotype (35.5 +/- 22.5 mg/dl) was higher than CC (4.1 +/- 2.8 mg/dl) and CT (20.4 +/- 11.2 mg/dl) genotypes of TGF-beta1 codon 10 (T-->C) gene polymorphism (P = 0.037). High producers of cytokine IL-10 -1082 [GG (n = 22) vs. AA + AG (n = 50)] and low producers of TGF-beta codon 25 [GC + CC (n = 17) vs. GG (n = 55)] had lower IMT of carotid artery but the difference did not reach statistical significance (P > 0.05). The CIMT of renal transplant patients was similar in IL-10 (-819, -592) and TNF-alpha (-308, -238) genotypes. No difference was observed in 24-h ambulatory blood pressure levels, serum lipoproteins, plasma homocysteine level, erythrocyte sedimentation rate, serum CRP, serum fibrinogen level in IL-10, TNF-alpha and TGF-beta1 genotypes. Besides the well-known factors, TGF-beta1 gene polymorphisms might play a role in CVD in RTR even at early stages of asymptomatic atherosclerosis.

Immune response genes in the post-Q-fever fatigue syndrome, Q fever endocarditis and uncomplicated acute primary Q fever

BACKGROUND

The influence of immune response gene variations on the development of chronic complications of Q fever is presently unclear.

AIM

To compare the frequencies of allelic polymorphisms in immune response genes in different Q fever patient groups.

DESIGN

Genetic association study.

METHODS

We measured the frequencies of immune response gene variants in: (i) an expanded group of 31 post-Q-fever fatigue patients (QFS); (ii) 22 Q fever endocarditis patients (QFE); and (iii) 22 patients who made an uncomplicated recovery from their initial attack of primary acute Q fever, comparing them with various standard control panels from the general population.

RESULTS

There were significant differences between the three Q fever groups. QFS patients differed from both QFE and uncomplicated patients and controls in the frequency of carriage of HLA-DRB1*11 and of the 2/2 genotype of the interferon-gamma intron1 microsatellite. Carriage of the HLA DRB1*11 allele was associated with reduced interferon-gamma and IL-2 responses from PBMC stimulated with ligand in short-term culture. QFE showed differences in the IL-10 promoter microsatellites R and G and had higher frequencies of the TNF-alpha receptor II 196R polymorphism. Q fever patients who had made an uncomplicated recovery differed from those with QFS or QFE, but were not significantly different in allelic frequencies to the control panels.

DISCUSSION

These immunogenetic differences support the concept of different immune states in chronic Q fever, determined by genetic variations in host immune responses, rather than by solely properties of Coxiella burnetii.

Association between TNF-α −308G>A polymorphism and the development of acute coronary syndromes in Greek subjects: The CARDIO2000-GENE Study

PURPOSE

We investigated the association of a polymorphism within the promoter of TauNuF-alpha locus at the position -308 on the likelihood of having acute coronary syndromes (ACS) in Greek adults.

METHODS

We studied demographic, lifestyle, and clinical information in 237 hospitalized patients (185 males) with a first event of an ACS and 237 matched by age and sex (controls) without any clinical evidence of coronary heart disease. Genotyping was performed by PCR-RFLP analysis.

RESULTS

The genotype frequencies were in patients, 87% (n = 206), 12% (n = 29), and 1% (n = 2) for G/G, G/A, and A/A, and in controls, 96% (n = 227), 4% (n = 10), and 0% (n = 0) for G/G, G/A, and A/A, respectively (P = 0.04). After adjusting for age and sex, as well as various potential confounders, we observed that G/A or A/A genotypes were associated with 1.94-fold higher odds (95% CI 1.06 to 3.68) of ACS compared to G/G homozygotes. No gene to-gender or to-clinical syndrome interactions were observed. Further subgroup analysis showed that the distribution of TNF-alpha -308G>A polymorphism was associated with the presence of family history of CHD in patients, but not in controls. In particular, in G/A and A/A patients 17.2% reported family history of CHD, whereas in G/G patients, 34.5% reported family history (P = 0.036).

CONCLUSIONS

Our findings may state a hypothesis of an association between the -308G>A TNF-alpha polymorphism the development of ACS and the presence of family history of CHD, in Greece.

Effect of the G-308A polymorphism of the tumor necrosis factor (TNF)-alpha gene promoter site on plasma levels of TNF-alpha and C-reactive protein in smokers: a cross-sectional study

Background

Plasma levels of tumor necrosis factor (TNF)-α and of C-reactive protein (CRP) are elevated in smokers. Previous studies failed to show an association between the G-308A polymorphism in the promoter region of the TNF-α gene and coronary artery disease (CAD). We investigated whether smoking would interact with the TNF-α G-308A polymorphism in determining plasma levels of TNF-α and CRP.

Methods

Study participants with a complete data set in terms of smoking and the TNF-α G-308A polymorphism were 300 middle-aged male and female industrial employees. After excluding 24 irregular smokers, analyses were performed on 198 "non-smokers" (life-long non-smokers or subjects who quit smoking >6 months ago) as compared to 78 "regular smokers" (subjects currently smoking >3 cigarettes/day). All subjects had a fasting morning blood draw to measure plasma levels of TNF-α and CRP by high-sensitive enzyme-linked immunosorbent assays.

Results

The cardiovascular risk factor adjusted analysis regressing log-transformed CRP levels against smoking status, genotype, and smoking-status-genotype interaction revealed a significant main effect for smoking status (F_1,250 = 5.67, p = .018) but not for genotype (F_1,250 = 0.33, p = .57). The interaction-term between genotype and smoking status was not significant (F_1,250 = 0.09, p = .76). The fully adjusted model with plasma TNF-α failed to show significant main effects for smoking and genotype, as well as for the smoking-status-genotype interaction.

Conclusions

The findings suggest that the TNF-α G-308A polymorphism does not mediate the effect of smoking on plasma CRP levels. It remains to be seen whether other genetic polymorphisms along the inflammatory pathway may modulate vascular risk in smokers.

Association of TNF-α gene promoter polymorphisms with outcome of hepatitis B virus infection

AIM: To investigate the polymorphism of tumor necrosis factor-a(TNF-α) gene promoters in Chinese Han people, and to clarify whether such polymorphism was associated with the outcome of hepatitis B virus infection.

METHODS: After the process of extracting genomic DNA from blood in 165 subjects who spontaneously recovered(SR) and 131 patients with chronic hepatitis B (CHB), four single nucleotide polymorphism (SNP) sites in TNF-α gene promoter marked as -238G/A, -308G/A, -857C/T and -863C/A were determined by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analysis.

RESULTS: Twelve different promoter genotypes were detected from all of 296 research subjects, and GG.GG.CC.CC, GG.GG.CC.CA, GG.GG.CT.CC, GG.GA.CC.CC genotypes accounted for about 85% of genotypes in these subjects. By analyzing the four promoter genotypes of TNF-α, the results showed that there were significant differences in the frequencies of GG.GG.CC.CC, GG.GG.CC.CA and GG.GA.CC·CC genotypes in TNF-α gene promoter between CHB and SR, GG.GG.CC.CC genotype carriers were at increased risk of CHB with an odds ratio of 2.15 (95% CI 1.34-3.45); While GG.GG.CC.CA and GG.GA.CC.CC genotypes carriers were at increased risk of CHB with an odds ratio of 0.48(95% CI 0.27-0.86) and 0.35 (95% CI 0.14-0.89), respectively. GG.GG.CC.CA and GG.GA.CC.CC genotypes were strongly associated with the resolution of HBV infection(χ² = 6.14, P = 0.013<0.05; χ² = 5.18, P = 0.023<0.05, respectively). Single site analysis also revealed that TNF-α gene -308G/A and -863C/A SNP sites were associated with persistent HBV infection in Chinese Han people (-308G/A site, χ² = 6.53, P = 0.011<0.05, OR=3.21; -863C/A site, χ² = 4.33, P = 0.037<0.05, OR=1.69, respectively).

CONCLUSION: There is an association between polymorphisms of the promoter region -308G/A and -863C/A of TNF-α and the resolution of HBV infection. The presence of the -308A allele (TNF-α-308GA) and /or -863A allele(TNF-α-863CA or AA) may be resistant to HBV infection, which gives some new clues to the study of pathogenesis of chronic hepatitis B.

Polymorphism of tumor necrosis factor-alpha and risk and severity of bronchopulmonary dysplasia among very low birth weight infants

BACKGROUND

Preterm infants with bronchopulmonary dysplasia (BPD) exhibit prolonged elevation of inflammatory indices in their tracheal aspirates. Tumor necrosis factor-alpha (TNF-alpha) is a central mediator of the inflammatory response. The adenine-containing alleles of TNF-alpha-308 and lymphotoxin-alpha+250 have been associated with increased levels of TNF-alpha, whereas the adenine allele of TNF-alpha-238 produces lower levels of TNF-alpha after stimulation. High levels of TNF-alpha may promote chronic inflammation by overwhelming counter-regulatory mechanisms and may lead to the development of BPD. Low levels of TNF-alpha may decrease the risk and/or severity of BPD.

OBJECTIVE

To determine whether alleles of TNF-alpha play a role in the susceptibility and/or severity of BPD among very low birth weight infants.

METHODS

Infants with birth weights of < or =1250 g were included. Genotypic analyses (polymerase chain reaction-restriction fragment length polymorphism assays) were performed with DNA extracted from whole-blood samples.

RESULTS

Infants who developed BPD (fraction of inspired oxygen at postconceptional age of 36 weeks of >0.21, n = 51) had a younger gestational age (mean +/- SD: 27 +/- 4 vs 29 +/- 2 weeks) and lower birth weight (853 +/- 184 vs 997 +/- 193 g) than did infants without BPD (n = 69). The genotypic distributions of lymphotoxin-alpha+250 and TNF-alpha-308 were comparable among the groups of infants. However, the AA and GA TNF-alpha-238 genotypes were much less likely to occur among infants with BPD than among infants without BPD. The adenine allele of TNF-alpha-238 was absent among infants with severe BPD and occurred significantly less often among infants with moderate or severe BPD, compared with infants with mild BPD. The number of adenine alleles of TNF-alpha-238 was correlated inversely with the severity of BPD (r = -.341).

CONCLUSION

The adenine allele of TNF-alpha-238 may reduce the risk and severity of BPD.